The electrocardiogram predicts one-year outcome of patients with unstable angina and non-Q wave myocardial infarction: Results of the TIMI III registry ECG ancillary study

Objectives. We sought to determine the prognostic value of the admission electrocardiogram (ECG) in patients with unstable angina and non-Q wave myocardial infarction (MI). Background Although the ECG is the most widely used test for evaluating patients with unstable angina and non-Q wave MI, little prospective information is available on ib value in predicting outcome in the current era of aggressive medical and interventional therapy. Methods. ECGs dth the qualifying episode of pain were analyzed in patients enrolled in the Thrombolysis in Myocardial Ischemia (TIMI) III Registry, a prospective study of patients admitted to the hospital with unstable angina or non-Q wave MI. Results New ST segment deviation greater than or equal to 1 mm was present in 143% of 1,416 enrolled patients, isolated T wave inversion in 21.9% and left bundle branch; block (LBBB) in 9.0%. By 1-year follow-up, death or MI occurred in 11% of patients with greater than or equal to 1 mm ST segment deviation compared with 6.8% of patients with new, isolated T wave inversion and 82% of those with no ECG changes (p < 0.001 when comparing ST with no ST segment deviation). live other high risk groups were identified: those with only 0.5-mm ST segment deviation and those with LBBB, whose rates of death or MI by 1 year were 163% and 22.9%, respectively. On multivariate analysis, ST segment deviation of either greater than or equal to 1 mm or greater than or equal to 0.5 mm remained independent predictors of death or MI by 1 year. Conclusions. The admission ECG is very useful in risk stratifying patients with non-Q wave MI. The new criteria of not only greater than or equal to 1-mm ST segment deviation hut also greater than or equal to 0.5-mm ST segment deviation or LBBB identify high risk patients, whereas T wave inversion does not add to the clinical history in predicting outcome. (C) 1997 by the American College of Cardiology.